Christmas at the Caverns Grounds Natural Bridge Caverns

The Natural Bridge Caverns of San Antonio are the largest-known caverns you can explore in Texas. The caves were discovered in the 1960s, but there's plenty of archeological evidence suggesting that humans were using the caves as far back as 5,000 BC.

The caves are explorable thanks to state-of-the-art lighting and handy paths that visitors can follow on self-guided underground tours. Outside, there are also courses for rope climbing and ziplining, suspended high above the ground.